A known sunroof apparatus for a vehicle is disclosed, for example, in JP2000-108676A, which will be hereinafter referred to as Reference 1. The sunroof apparatus disclosed in Reference 1 is a so-called outer sliding sunroof including a link mechanism for supporting a movable panel. Specifically, the link mechanism includes a rear lift link performing a swinging motion by a sliding operation of a first shoe, a front lift link performing a swinging motion by a sliding operation of a second shoe, and a connecting rod connecting the rear lift link and the second shoe so that the second shoe is slidably operated (i.e., performs the sliding operation) by the swinging motion of the rear lift link. In a case where the first shoe is slidably operated (i.e., performs the sliding operation), the rear link performs the swinging motion to lift up a rear end of the movable panel. During the aforementioned process, the swinging motion of the rear lift link is transmitted to the second shoe via the connecting rod. The resulting sliding operation of the second shoe causes the front lift link to perform the swinging motion to thereby lift up a front end of the movable panel. As a result, the movable panel is tilted up (i.e., performs a tilt-up operation).
Thereafter, the first shoe and the second shoe are slidably operated so that the movable panel slides outward (above a roof portion of a vehicle) while the movable panel is maintained to be tilted up (i.e., maintained in a tilt-up state). An opening formed at the roof portion is brought to an open state accordingly. At this time, the rear lift link performs the swinging motion by a function of an engagement structure provided between the rear lift link and the first shoe. Thus, because of specification of the engagement structure, the movable panel may be slowly tilted-up.
According to the sunroof apparatus disclosed in Reference 1, a moving amount (i.e., an operation stroke) of the first shoe or the like by which the movable panel is brought to a fully open state from a fully closed state is specifically the moving amount by which the movable panel is brought to the fully open state via the tilt-up state from the fully closed state. Thus, in a case where the moving amount of the first shoe or the like by which the movable panel is brought to the tilt-up state from the fully closed state (hereinafter also referred to as a tilt operation stroke) increases, the moving amount of the first shoe or the like by which the movable panel is brought to the fully open state, i.e., an amount of opening of the movable panel, may be difficult to be secured.
On the other hand, because the tilt operation stroke corresponds to an area of a high load state where the movable panel moves upward and downward, it is desirable for the tilt operation stroke to be elongated. When it is assumed that the tilt operation stroke is shortened, a load per unit operation stroke increases, which may result in an enlargement of an electric drive source (for example, a motor) for driving the first shoe or the like.
According to a sunroof apparatus for a vehicle serving as an outer sliding sunroof disclosed in JP4109583B which will be hereinafter referred to as Reference 2, it is proposed that a guide rail on which a shoe slidably moves projects forward in a state to penetrate through a front frame (housing). Accordingly, a supporting span of the movable panel may be widened while the opening amount of the movable panel increases or without deterioration of the opening amount of the movable panel.
Nevertheless, an effect obtained by the increase of the opening amount of the movable panel by the penetration of the guide rail through the front frame, for example, is insignificant. The opening amount of the movable panel is still difficult to be secured.
A need thus exists for a sunroof apparatus for a vehicle which is not susceptible to the drawback mentioned above.